For several years I have written a series of articles outlining my projections for various digital storage and non-volatile memory technologies for the coming year and beyond. This will be the first of my projection articles for 2025, focusing on magnetic recording technology, particularly hard disk drives (HDDs) and magnetic tape.
The general recession in HDD demand (as well as other digital storage and memory products) that began in 2022 and continued through most of 2023 appears to have ended in 2024. To be clear, the long-term decline in demand for legacy HDD applications such as personal computers and consumer electronics continued in 2024, due to replacement by SSDs and cloud storage, which may include HDDs, but nearline high-capacity HDDs rather than smaller capacity HDDs. Unit shipments of these legacy HDDs was down over 20% year over year.
However, the unit volume shipments of high capacity nearline HDDs is projected to have increased about 42% in 2024 from 2023. In 2023 these high capacity nearline HDD unit shipments had declined by about 37% from 2022 after a 15% Y/Y decline in 2022. By 2024 excessive inventories of nearline HDDs was exhausted and demand had increased for low-cost storage of data for AI and other data-intensive computer applications.
Results for the final quarter of 2024 have not been announced, but my estimates project that overall HDD unit shipments in 2024 will be about 2% higher than in 2023, at about 124M units, the first year over year shipment growth since 2010, although starting from a low number from the 2022-2023 storage recession. HDD capacity shipments are estimated to increase about 39% from 2023 to 2024, to 1.2 ZB, and gross HDD revenues may increase by about 45%, to $19.5B, in 2024 compared to 2023. We project total HDD capacity shipments will be about 7.3ZB by 2029.
The figure below shows HDD shipment history as well as high, median and low estimates for HDD shipments out to 2029.
Market share for HDD shipments from the three HDD manufacturers in 2024 is estimated at about 40% each for Seagate and Western Digital and 20% for Toshiba.
The HDD companies indicate that they are entering into long term agreements with major customers to ensure meeting the customer’s anticipated demand and to prevent manufacturing excess products. Overall, HDD average sales prices increased in 2024 as shown in the figure below with HDD ASP history from 1998 through Q3 2024. Q3 2024 HDD ASP prices are as high now as they were in at the end of the last century, mostly due to the increased percentage of higher priced nearline HDDs, but with some contribution from higher nearline HDD prices in 2024.
Nearline HDDs are about 54% of shipments in 2024 and are expected to be over 90% of shipments by 2029.
Increasing storage capacity per drive results in lower prices per bit of data ($/TB). For high-capacity enterprise and data center HDDs, helium sealed drives with more disks allows higher capacities. Currently these drives are available with up to 11 disks (with WDC’s recent 32TB SMR drive introduction). More disks may be possible, maybe even up to 12 disks, but this would require moving these drives to thinner glass substrates which would be stiffer than aluminum substrates as well as changes to the magnetic head height and the head suspensions.
HDD capacities can also be increased by shingling the tracks, partially writing new tracks over existing tracks, although as the drive gets full, writing new data requires moving good data to another location and then writing the new and good data again (a process somewhat like the erase and write process for SSDs). This type of shingled magnetic recording or SMR drive is most effective for write-seldom applications and WDC says that they have a robust market demand for SMR HDDs.
HDD capacities can also be increased by increasing the track density or the linear density of the information recorded on the concentric tracks. Track density increases have slowed down, however, energy assisted magnetic recording where energy is applied to very stable magnetic recording media (having high magnetic coercivity) to allow it to be written on, is the best hope for increasing the linear density of magnetic recording.
WDC is currently using what they call ePMR, which stabilizes the written bits and which they call a form of energy assisted recording. This is used in their latest nearline HDDs, including the 11-disk products, which combined with their OptiNAND technology and SMR, can achieve 32TB capacities. Toshiba says that they are using a form of micro-wave assisted magnetic recording, MAMR, in their high -apacity HDDs but that future 30+TBHDDs will include heat assisted magnetic recording, HAMR, as well.
Seagate is also using HAMR in their recently announced 30TB HDDs that uses lasers to heat the disk surface during writing. The company plans to go into mass production of 30+TB HDDs by mid-2025. Shingled versions of these HAMR drives could offer close about 36TB of capacity. Seagate has indicated that it expects to have 40+TB products available by 2026-2027 and 50+TB HDDs by the end of the decade.
With its introduction of HAMR HDDs in 2024 and planned drive capacity increases, Seagate could have a significant advantage over WDC and Toshiba for at least a few quarters since ePMR and MAMR will likely not be able to deliver such high per disk storage capacities. In order to match these HDD capacities WDC will need to either ramp up its own HAMR HDD program or it, along with Toshiba, will need to buy HAMR heads from TDK, and perhaps HAMR media from Resonac (formerly known as Showa Denko). Both companies are believed to be working together to develop HAMR products.
Seagate and WDC have shipped some dual actuator HDDs (where the rotary actuator is split into two effective actuators on the same rotating point) in the past few years, but this technology hasn’t taken off. It is expected that these dual actuator HDDs (which Seagate calls its Mach-2 HDDs) will become standard fare on higher capacity HDDs, such as for 40TB and higher HDDs, since they can increase performance and, more importantly, increase rebuild time for failed drives.
The figure below shows the most recent HDD technology roadmap from the Advanced Storage Research Consortium (ASRC), from the 2022 IEEE TMRC conference. ASRC is HDD industry consortium that provides projections on storage density growth (areal density is the average amount of information stored per area on the HDD disks). This image shows projections for over 10 Tbpsi HDDs by the mid-2030’s (which should provide over 200TB HDDs) using a combination of technologies that includes HAMR.
The figure below shows the history and our projections for declining price of HDD storage in $/GB, with projections out to 2029. Note the temporary increase in prices in 2024 due to constrained production capacity.
Magnetic tapes also use magnetic recording, but the areal density of magnetic tape is many generations behind HDDs. This gives magnetic tape significant future technology for increasing storage capacity in the future. However magnetic tape is different than HDDs since it uses flexible media and multiple tracks are written or read at a time.
This means that magnetic tape, once mounted in a tape drive, has data rates much greater than HDDs. HDDs are increasingly used for nearline storage while magnetic tape is used to store colder data and for archiving. The primary magnetic tape technology is LTO, with over 80% of the market with IBM enterprise tape providing the balance.
In August of 2023 IBM announced its TS1170 magnetic tape drive, supporting storage capacities up to 50TB native and higher capacities with compression. The product has a native data rate of 400 MB/s and has 12Gb SAS and 16Gb Fibre Channel interface options. These drives support new tape cartridge media using Strontium Ferrite magnetic particles. The JF media is produced by Fuji Film, who also makes LTO media. This 50TB tape cartridge technology was a 2.5X increase from prior generation 20TB products.
LTO magnetic tape is the most used with LTO 9 tape the highest capacity LTO tape shipping today. LTO 9 was introduced in 2019 but wasn’t generally available until September 2021. These tapes have a native capacity of 18TB (with an areal density of recording about 1/100th that of HDDs). In 2022 the LTO tape consortium expanded its roadmap to LTO generation 14 with up to 576TB of native storage capacity. This roadmap is shown below.
It is expected that LTO 10 products will be announced sometime in 2025 although they may not provide double the capacity of the 18TB LTO 9 tapes, or 36TB of raw tape cartridge capacity. However, if new LTO generations are introduced about every three years, which has been typical, and if each generation has double the capacity of the prior generation, then LTO 14 could be available in about 2036, with 576TB native tape cartridge capacity at about the same time as possible 200TB HDDs.
Tape manufacturers have been promoting magnetic tape as a more sustainable storage media, since little energy is used when magnetic tape cartridges are sitting on shelves. Fujifilm estimates that about 43% less carbon emissions result from the use of magnetic tape compared to HDDs.
The total market for magnetic tape media, drives and libraries is probably over $2B. IBM is the sole manufacturer of magnetic tape drives and Fujifilm and Sony are the only manufacturers of magnetic tape media. We estimate that total tape capacity shipments in 2024 will be 204EB and that this will climb to 411EB by 2029.
HDD unit shipments will be up about 2% in 2024 versus 2023 and shipped capacity will be up about 39%. By the 2030’s we could have 200TB HDDs and 576TB tapes.
